Most mobile devices are configured to receive and operate removable Universal Integrated Circuit Cards (UICCs) that enable the mobile devices to access services provided by mobile network operators (MNOs). In particular, each UICC includes at least a microprocessor and a read-only memory (ROM), where the ROM is configured to store different applets and authentication data that the mobile device can utilize to register and interact with the MNOs. Typically, a UICC takes the form of a small removable card (e.g., a SIM card) that is configured to store a single MNO profile and be inserted into a UICC-receiving bay included in a mobile device. In more recent implementations, however, UICCs are being embedded directly into system boards of mobile devices and are configured to store multiple MNO profiles (e.g., electronic SIMs (eSIMs))—e.g., one eSIM for a local MNO, and another eSIM for an international MNO. Notably, these embedded UICCs (eUICCs) provide several advantages over traditional, removable UICCs. For example, some eUICCs include a rewritable memory that can facilitate eSIM updates for accessing extended features provided by MNOs. EUICCs can also eliminate the necessity of including UICC-receiving bays within mobile devices. The implementation of eUICCs therefore not only increases the flexibility of mobile devices, but also simplifies their design and frees up space for other components.
Despite the foregoing advantages provided by eUICCs, new challenges continue to arise with respect to maintaining a high level of security and robustness while providing the increased flexibility. Consider, for example, a common scenario that involves a new, out-of-the-box mobile device whose eUICC stores only one eSIM. In this example, the eSIM is associated with a Type parameter that indicates to the eUICC that the eSIM is a bootstrap-type eSIM that can be used to access a limited service provided by an MNO (e.g., a subscription registration service). In turn, the eUICC activates the bootstrap-type eSIM, and, when a user of the mobile device completes the subscription registration service, an operator-type eSIM that enables the mobile device to access standard services provided by the MNO (e.g., voice calls and internet) is downloaded and stored into the eUICC. Consider further that, at a subsequent time, the MNO issues to the eUICC an over-the-air (OTA) update that erroneously updates the Type parameter associated with the operator-type eSIM and causes the operator-type eSIM to become a bootstrap-type eSIM. Consequently, when the mobile device power cycles and interfaces with the eUICC to obtain access to the MNO, only two bootstrap-type eSIMs are identified by the eUICC and the mobile device is prevented from accessing the standard services provided by the MNO. This not only creates confusion for the user, but could potentially send the user back to the registration process that he or she already completed, thereby degrading the user's overall experience.